Upcycling Low-Nickel Polycrystalline Cathodes from Retired Electric Vehicle Batteries into Single-Crystal Nickel-Rich Cathodes

TL;DR

This paper introduces an environmentally friendly method for recycling retired EV batteries by converting low-nickel cathodes into high-nickel single-crystal NMCs, enhancing energy density and electrochemical performance.

Contribution

It presents a novel molten salts direct-recycling process for upcycling low-nickel cathodes into high-nickel single-crystal NMCs with improved properties.

Findings

Successful upcycling of low-nickel cathodes into Ni-rich single-crystal NMCs.

Achieved over 10% increase in energy density.

Demonstrated >94% capacity retention after 500 cycles.

Abstract

The electrification revolution in automobile industry and others demands annual production capacity of batteries at least on the order of 102 gigawatts hours, which presents a twofold challenge to supply of key materials such as cobalt and nickel and to recycling when the batteries retire. Pyrometallurgical and hydrometallurgical recycling are currently used in industry but suffer from complexity, high costs, and secondary pollution. Here we report a direct-recycling method in molten salts (MSDR) that is environmentally benign and value-creating based on a techno-economic analysis using real-world data and price information. We also experimentally demonstrate the feasibility of MSDR by upcycling a low-nickel polycrystalline LiNi0.5Mn0.3Co0.2O2 (NMC) cathode material that is widely used in early-year electric vehicles into Ni-rich (Ni > 65%) single-crystal NMCs with increased energy-density (>10% increase) and outstanding electrochemical performance (>94% capacity retention after 500 cycles in pouch-type full cells). This work opens up new opportunities for closed-loop recycling of electric vehicle batteries and manufacturing of next-generation NMC cathode materials.